For enhancing the availability of the bicycle and reducing the physical strength burden for the bicycle rider, the various motorized bicycles that using motor driving means to replace for conventionally manually pedal driving means are introduced into the market with popular acceptance. Currently, the motor driving means of the conventional motorized bicycle are classified into four categories by transmission contrivance as below:
First category is directly motor driving bicycle that a motor is externally installed on the front wheel or rear wheel with motor shaft being parallel to the wheel axle.
Second category is directly motor driving bicycle that a motor is installed on the frame over front wheel or rear wheel externally with motor shaft being perpendicular to the wheel axle.
Third category is directly motor driving bicycle that a motor is internally installed in the hub of front wheel or rear wheel so that the motor is rotated with the installed wheel integrally.
Fourth category is indirectly motor driving bicycle that a motor is externally installed at suitable distal place away from the driven front sprocket with motor shaft being perpendicular to the transmission axle so that the motor driving torque is exerted on the driven front sprocket via a transmission element.
So far, the directly motor driving type of first, second and third motorized bicycle categories enjoy dominantly big market share while fourth motorized bicycle category takes trivially petty market share.
The driving means for the first motorized bicycle category is almost as shown in the FIG. 1, which illustrates the new model patent of Taiwan Published No. 522964. For this conventional motorized bicycle, the driving motor A1 is externally installed on the rear wheel with motor shaft being parallel to the axle of the driven rear wheel. By means of a transmission element A2, the motor driving torque is exerted on the driven rear sprocket A3, which firmly fixed on the driven rear wheel.
The driving means for the second motorized bicycle category is almost as shown in the FIG. 2. For this conventional motorized bicycle, the driving motor B1 is installed on the frame B2 over rear wheel externally with motor shaft being perpendicular to the axle of the driven rear wheel. By means of a transmission element, the motor driving torque is exerted on the driven rear sprocket B3, which firmly fixed on the driven rear wheel.
The driving means for the third motorized bicycle category is almost as shown in the FIG. 3, which illustrates the new model patent of Taiwan Published No. M259755, or in the FIG. 4, which illustrates the new model patent of Taiwan Published No. 467091.
For the conventional motorized bicycle shown in the FIG. 3, the driving motor C1 is internally installed in the hub of front wheel C2 directly so that the motor is rotated with the installed front wheel C2 integrally in coaxial manner. By means of such transmission, the motor driving torque is directly exerted on the hub of driven front wheel C2.
For the conventional motorized bicycle shown in the FIG. 4, the driving motor D1 is internally installed in the hub of rear wheel D2 directly so that the motor is rotated with the installed rear wheel D2 integrally in coaxial manner. By means of such transmission, the motor driving torque is directly exerted on the hub of driven rear wheel D2.
The driving means for the fourth motorized bicycle category is almost as shown in the FIG. 5, which illustrates the new model patent of Taiwan Published No. 192351, or in the FIG. 6, which illustrates the new model patent of Taiwan Published No. 519087.
For the conventional motorized bicycle shown in the FIG. 5, the driving motor E1 is externally installed at tubular front stem away from the driven front sprocket E2 with motor shaft being perpendicular to the transmission shaft E3. Via a chain E5, by means of a transmission element E4, which is parallel to the driven front sprocket E2, the motor driving torque is indirectly exerted on the hub of driven front wheel E2, which further drives the rear wheel via another chain to rotate forwardly.
For the conventional motorized bicycle shown in the FIG. 6, the driving motor E1 is externally linked on the driven front sprocket F2 directly via bevel gears with motor shaft being perpendicular to the transmission shaft F3. By means of a transmission device F5 (as shown in the FIG. 7), which is coupled to the driven front sprocket F2, the motor driving torque is indirectly exerted on the hub of driven front wheel F2, which further drives the rear wheel via a chain F4 to rotate forwardly.
However, some drawbacks respectively exist in the four motorized bicycle categories aforesaid as below:
1. For directly motor driving bicycles of first, second and third categories,
the motor (such as A1, B1, D1 and E1) is externally installed on the front wheel or rear wheel without taking advantage of employing the function of derailleur so that not only the flexibility and availability in slope-climbing capability is reduced but also the more power and physical effort are consumed comparing to that motorized bicycle having derailleur installed thereon.
2. For the first motorized bicycle category as shown in the FIG. 1, since the driving motor A1 is externally installed on the rear wheel via a transmission element A2 to relay the motor driving torque to the driven rear sprocket A3, relatively longer transmission element A2 (such as chain or belt) is required due to big diameter of the rear wheel so that not only the cost of transmission element A2 is rather high but also the dropping off the transmission element A2 becomes easy due to fluctuation in the tautness and relaxation.
3. For the second motorized bicycle category as shown in the FIG. 2, since the driving motor B1 is installed on the frame B2 over rear wheel externally with motor shaft being perpendicular to the axle of the driven rear wheel, a special angled transmission element such as a set of bevel gears are required to relay the motor driving torque to the driven rear sprocket B3. The set of bevel gears serving as angled transmission element here is a precision and expensive mechanical part subject to frequent lubrication timely. Moreover, since such driving motor B1 is externally installed on one side of the frame B2, not only the serious transverse weight imbalance will incur but also the space is reduced thereby so that the pillion footrest is difficult to be suitably disposed.
4. For the third motorized bicycle category as shown in the FIG. 3, where the driving motor C1 is internally installed in the hub of front wheel C2 directly so that the motor is rotated with the installed front wheel C2 integrally in coaxial manner, and the other motorized bicycle shown in the FIG. 4, where the driving motor D1 is internally installed in the hub of rear wheel D2 directly so that the motor is rotated with the installed rear wheel D2 integrally in coaxial manner. The motor C1 or D1 used here is an expensive tailor-made motor, which is susceptible to bounce if not well-adjusted, so that not only the cost is increased but also the bicycle is vulnerable to bumpy road. Moreover, the wheel used here is customized product instead of standardized one that also incurred higher cost bother.
5. For the rare fourth motorized bicycle category as shown in the FIG. 5, where the pedal crank and the front sprocket E2 are together driven by the driving motor E1 when in motor driving operation mode so that the rider must lift his/her feet up to avoid from being hit by the pedals or pedal crank. Besides, the extra load in meaninglessly driving pedal crank curtails the power supplying time in consequence of the incurrence of electric energy waste.
For the other design of same category as shown in the FIG. 6, since the transmission element F5 and the driven front sprocket F2 are externally installed at the same side (as shown in the FIG. 7), not only the serious transverse weight imbalance will incur but also the space is reduced thereby so that the transmission device F5 is difficult to be suitably disposed. In worse case, the integral strength of the bicycle will be reduced even the transmission device F5 is installed. Moreover, the transmission device F5 (as shown in the FIG. 7) used here comprises a set of bevel gears and a single-direction irreversible transmission element F51, wherein, said set of bevel gears, as stated above, serving as angled transmission element here is a precision and expensive mechanical part subject to frequent lubrication timely; and the complicated structural shape of said single-direction irreversible transmission element F51 (as shown in the FIG. 8) make itself should be specially customized through difficult process with very high cost.
6. The pedal driving operation mode is in need if no electric power is supplied for all four motorized bicycle categories aforesaid. The pedal driving force is not only used to drive the bicycle but also simultaneously to drive the extra cumbersome load of the idle motor, which is more than the load of single bicycle due to magnetic attraction between the stator and the rotor.
Realizing and addressing all the drawbacks aforesaid, the applicant of the present invention devotes himself to study, research and develop to improve the driving mechanism for the motorized bicycle. Eventually, the “driving mechanism for the motorized bicycle” of the present invention is successfully contrived after constantly experiments and improvements.